Characteristics of natural rocks used in experimental tests.
\r\n\t a multi-pronged approach. The pervasive computing paradigm is at a crossroads where never before computing
\r\n\t has been so much embedded within the user. Recent developments in sensor technologies, wireless protocols
\r\n\tintegration, and AI have empowered the citizen towards a smart citizen with a high degree of autonomy and varying
\r\n\tcomputing capabilities from one context to another.
\r\n\tMoreover, software engineering has evolved too to allow lightweight programming and full-stack coding of those sensors. The network itself is today viewed as a programming platform, thus wearable devices are no more stand-alone and do not operate in a vacuum. This book aims at attracting authors from academia, the industry, research institutions, public and private agencies to provide the findings of their recent achievements in the field, but also visionaries who foresee the future of wearable technologies in the coming decades.
Natural stone industry is one of the most effective actors of the Turkish mining industry economy. With its 4000-year history of natural stone production, Turkey is one of the oldest natural stone producers in the world. Natural stones are classified as metamorphic, sedimentary and magmatic according to their formations . Marble is a metamorphic rock formed by recrystallization of limestone. Marble is a metamorphic stone composed of calcite (CaCO3) and formed as a result of the recrystallization of the limestone under excessive pressure and heat [2, 3, 4, 5, 6]. CNC machines are electromechanical systems that process the materials according to the logical operation unit of numerical control (NC) codes defined by numbers, letters, and symbols of a product designed using a computer-aided design and manufacturing (CAD/CAM) program. Nowadays, 3D design in the natural stone industry can be processed with high accuracy, precision series and quality the use of CNC machine [7, 8]. Various processing technologies are used at natural stone quarries and factories to manufacture as building materials. In quarries, in the production of natural stone blocks, diamond wire cutting and chain arm cutting machines are widely used in factories, plates and panels manufacturing in the production of block cutter ST and gangsaw machines [9, 10, 11, 12, 13, 14, 15, 16, 17, 18].\n
CNC machine is used to process natural stone blocks and wastes in 3D design products to be used in buildings. Many studies have been found on the Cf in circular saws depending on the physicomechanical properties of natural rocks, modeling of the Se and socket [19, 20, 21, 22, 23], the definition of the theoretical chip geometry , and connections between tangential cutting force and chip thickness [25, 26, 27]. Some other studies address the effect of processing parameters on tool wear [28, 29, 30, 31], the modeling of natural stone cutting with diamond cutting tools  and specific grinding energy of chip samples under a scanning microscope  in order to determine specific cutting energy and power consumption [34, 35]. Energy and the type of cutting mechanism used in the production of end products from natural rocks lead to the wear of cutting tools. Energy consumption and wear of cutting edges are the important factors affecting processing costs. These factors should be efficiently to reduce processing costs. It is therefore important to determine the cutting performance of natural rocks according to their characteristics. Cut tools should be selected carefully and performance forecast should be proper in order to improve the processing efficiency of natural rocks and reduce costs. Different from the manufacture of plates and panels in which gangsaw and cutter ST are deep cut on the x (length), z (depth) axis, this process requires few depth cut and precision tools with a CNC machine on the x (length), y (width) and z (depth) axis. Cf, Sc and wear of diamond cut tools have a low spindle and Va in the processability of rocks in the CNC machine with internally cooled cut tools. Carbide coated end mills tools are widely used in the natural stones sectors. In addition, the number of studies on parameters affecting the processability of natural rocks in the CNC machine is less [36, 37, 38, 39, 40].\n
This study investigated the relationship between the values of the Cf, Se and Sc obtained from the processing of rocks using CNC, and related parameters (i.e., cutting parameters and physicomechanical properties). Cf, Se and Sc values depending on the dp and Va of natural rocks have been analyzed (ANOVA) statistically. Results show that 1.0, 1.2 and 1.6 mm at the dp and 2000, 2500, 3000 mm/min at the Va are important cutting parameters in the processability of natural rocks. Regression models were developed for the estimation of Cf, Se and Sc of the with measured by power and load meter tester. Regression analyses were performed to determine the optimum relationship between the Cf, Se and Sc dependent variable and physicomechanical properties independent variable in three different groups of natural rocks. Regression models developed in this study can be used by planners and natural stone manufacturing companies for cost analysis and mill cut tool processing programs in natural rocks. We recommend that it be considered in further studies use a larger database to analyze the possibility of regression analyses the Cf, Se and Sc any of the physico-mechanical parameters of natural rocks.\n
These natural rock samples were obtained from the companies operating a quarry in Afyon. The surface of each series was adjusted with the cutting process as a square (30 by 30-cm) and 1 cm thickness. Furthermore, these rock samples were polished on one side. Table 1 shows sample code, pertographic name, dimensions, main modal compositions, sample number and surface processing of the rocks used in the test.\n
|Natural rocks\n||Sample code\n||Pertographic name\n||Main modal compositions\n||Dimensions (mm)\n||N\n||Surface processing\n|
|Travertine\n||T1-T5\n||Sedimentary\n||Calcite\n||300 × 300 × 30\n||15\n||Polished\n|
|Marble\n||M1-M7\n||Metamorphic\n||Calcite\n||300 × 300 × 30\n||15\n||Polished\n|
|Limestone\n||K1-K5\n||Sedimentary\n||Calcite\n||300 × 300 × 30\n||15\n||Polished\n|
Cut tool (carbide-coated end-mill cutting edge tool) was used in the processing of natural rocks by CNC machine. Figure 1 shows the image of the end mill cut tool. Table 2 shows the technical specifications of the end mill cut tool.\n\n
|Cutting tool diameter/d1\n||mm\n||6\n|
Figure 2 shows that the CNC consists of the machine, electric motors, pneumatic or hydraulic power units, control panel and software.\n\n
A 4-Axis CNC (Megatron) machine designed for the natural stone industry in Afyon Kocatepe University Natural Stone Processing Laboratory was used for the tests. The technical features of the machine are given in Table 3.\n
|Spindle motor (kW)\n||9.0\n|
|Number of axis (number)\n||4.0\n|
|Motor speed (rpm)\n||24.000\n|
|Processing speed (rpm)\n||24.000\n|
|Vamotor x axis (mm/dk)\n||80.000\n|
|Processing length (mm)\n||4.000–4.500\n|
|Processing width (mm)\n||2.000–2.500\n|
|Processing height (mm)\n||500–600\n|
|Lathe height (mm)\n||700–750\n|
|Lathe length (mm)\n||2.500–3.000\n|
|Automatic number of teams (adet)\n||8.0\n|
Processability tests were performed on natural rocks according to the dp and Va cutting parameters by using CNC machine. Alpha CAM drawing program was used to determine the cutting parameters of natural rocks. As shown in Figure 3, 120 × 25 mm in size 18 rectangular samples were produced using a 3D modeling and simulation program for the processability tests.\n\n
A power meter, also known as load meter, built in the CNC machine was used in the processability tests. This testing tool consists of a measurement unit, a load cell, a controller unit and Defne Lab Soft program (Figure 4).\n\n
Natural stone samples were bond and stabilized to the platform on the measurement unit with cut tools. There were 4 on the Z axis, 4 on the X and Y axis total 8 load cells on the testing machine to calculate the Cf. Defne Lab-Soft program was recorded into the data input screen of types and sizes of natural rocks, cutter information, and constant and variable parameters. NC codes from Alphacam drawing program were transferred to the CNC machine with Recon program interface. The cut tool was balanced to the engine of the CNC machine connected to the tool holder. The reset operation was performed when the cutting tool was guided by the function and operation keys to the reference point on the test specimen surface. NC code was selected using the function and operation keys on the control unit and the measurement was performed by pressing the start button. Depending on the different process parameters, the natural stones were processed in the cooling process from the water flow rate of 1 l/min. A rectangle of 120 × 25 mm was processed for 40 s to obtain 100 data per second. All samples were processed in a total of 84 min. Figure 4 shows a schematic view of the test apparatus.\n
In the processability tests, variable and constant parameters were taken into consideration. Constant cutting parameters were the cut tool diameter of 6.0 mm, spindle speed of 10,000 d/min, cutting width of 3.0 mm and plunge speed of 1000 d/min. Variable cutting parameters were the dp of 1.20, 1.60 and 2.0 mm and Va of 2500, 3000, 3500 mm/min. Table 4 shows the CNC cutting parameters for the natural rocks processed in the tests.\n
|Cutting tool diameter\n||mm\n||6.0\n|
|Depth of cut\n||mm\n||1.20–1.60–2.00\n|
Figure 5 explains the vector representation of the forces (Fx, Fy, Fc and Ft), Vt and Va that occurred during the processing of the natural rocks.\n\n
Calculation of Fx cutting force according to CNC processing parameters is as shown in Eq. (1).\n
Fx cutting force Eq. (1);\n
Fx = cutting force (N); Fx1 = absolute forward cutting force (N); Fx2 = absolute back cutting force (N).\n
Fy cutting force Eq. (2);\n
Fy = cutting force (N); Fy1 = absolute forward cutting force (N); Fy2 = absolute back cutting force (N).\n
Calculation by using R resultant force, Fx and Fy cutting forces, Eq. (3):\n
R = resultant force (N); Fx = cutting force (N); Fy = cutting force (N).\n
β angle between R and Fx, Eq. (4),\n
Contact angle θ between tool diameter (d) and natural rocks, Eq. (5);\n
Calculating Fc tangential force and radial force Ft components of the cutting forces with the R value obtained.\n
δ angle between Ft and Fc.\n
Parameter Z depends on the location of the application point of the compound forces R on the arc AC, which is contact between cutting edges and natural rocks.\n
Parameter Z, Eq. (9):\n
Vt cutting speed Eq. (10):\n
Vt = cutting speed (m/min); n = spindle speed (d/min); D = cutter diameter (mm).\n
Specific cutting energy depending on tangential force and cutting speed is shown in Eq. (11).\n
Fc = tangential cutting force (N); Vt = cutting speed (m/min); Va = feed speed (mm/min); dp = cutting depth (mm); b = cutting width (mm).\n
Se values were calculated using the power P and Qw obtained from the main electric motor of 7.5 kW where the cutting end of the natural rocks was connected during the processability time (t).\n
The chip volume is shown in Eq. (12).\n
Qw = chip volume (mm3); b = size of the sample (mm); l = the width of the sample (mm); dp(1,2,3) = cutting depth (mm).\n
The total specific energy is shown in Eq. (13).\n
Se = total specific energy (J/mm3); P = power consumption (W); t = total time (s); Qw = chip volume (mm3).\n
The petrographic analysis was carried out in the MTA (General Directorate Mineral Research and Exploration) mineralogical and petrographic analysis laboratory in Ankara/Turkey. Chemical properties of natural rocks were performed using the XRF (X-ray fluorescence) method in ACME (Analytical Laboratory in Turkey/Ankara). The metamorphic (marble) and sedimentary (travertine, and limestone) origin natural rocks used in this study had different textures. All natural rock types were composed of CaO as main calcite crystals and at least 99.0% calcite minerals ranging from 53.10 to 55.70%. The petrographic analysis results and chemical analysis of the samples are presented in Tables 5 and 6, respectively. Petrographic and chemical analysis results of samples are given in Tables 5 and 6, respectively.\n
|Natural Rocks\n||Petrographic descriptions\n||Minerals\n|
|T1\n||Fine-grained calcite is the dominant mineral. Consist of micro-mesocrystalline calcite minerals with a little amount of clay. Often contains pores. Micritic (intraclast) texture. Travertines\n||77% Calcite (mic), 22% Calcite (spr)\n|
|T2\n||78% Calcite (mic), 21% Calcite (spr)\n|
|T3\n||79% Calcite (mic), 20% Calcite (spr)\n|
|T4\n||78% Calcite (mic), 21% Calcite (spr)\n|
|T5\n||77% Calcite (mic), 22% Calcite (spr)\n|
|M1\n||Fine, medium, medium-coarse and coarse-grained with polysynthetic twins, granoblastic texture. Marbles\n||98.5% Calcite\n|
|M7\n||97% Calcite, 2% dolomite\n|
|K1\n||Fine-grained. Consists of cryptocrystalline calcite within crypto microcrystalline calcite. Micritic texture. Limestones\n||96% Calcite (mic), 2% Calcite (spr)\n|
|K2\n||96% Calcite (mic), 2% Calcite (spr)\n|
|K3\n||95% Calcite (mic), 3% Calcite (spr)\n|
|K4\n||95% Calcite (mic), 3% Calcite (spr)\n|
|K5\n||95% Calcite (mic), 3% Calcite (spr)\n|
|Natural Rocks\n||CaO (%)\n||SiO2 (%)\n||Al2O3 (%)\n||Fe2O3 (%)\n||MgO (%)\n||K2O (%)\n||TiO2 (%)\n||P2O5 (%)\n||MnO (%)\n||LoI (%)\n|
The CNC processability tests were conducted in the Rock Mechanics and Technology Application and Research Center Laboratory of the Department of Mining Engineering of Afyon Kocatepe University. The tests were performed in accordance with Standard No. TS EN 1936: 2010 , Standard No. TS EN 13755: 2014 , Standard No. TS EN 14205: 2004 , Standard No. TS EN 1926: 2007 , Standard No. TS EN 13161: 2014 , Standard No. TS 699  and Standard No. TS EN 1341 (Appendix-C: 2013) . The physicomechanical properties of the natural rocks are presented in Table 7. The rock samples were 40 × 40 mm3, 70 × 70 × 70 mm3 and 30 × 50 × 180 mm3. The tests were carried out using at least six samples.\n
|Natural Rocks\n||D (kg/m3)\n||P (%)\n||WA (%)\n||KH\n||UCS (MPa)\n||FS (MPa)\n||IS (MPa)\n||AR (cm3/50 cm2)\n|
In processability tests, the Fc and Ft measurements were conducted using two-factor analysis of variance (ANOVA) (17 natural rocks × 2 Cf × 3 dp × 3 Va) randomized experimental design with 100 replications (n = 100). A total of 30,600 data were obtained on the rocks. In terms of the Cf (Fc, Ft), among the dp and Va there was a statistically significant difference (P < 0.001) (Table 8).\n
|Cf (N) dependent variable\n||dp (mm)\n||Mean difference (I-J)\n||Std. Error\n||Sig.\n||95% confidence interval\n|
|\n||Mean (I)\n||Mean (J)\n||Lower bound\n||Upper bound\n|
In processability tests for natural rocks, the mean Fc and Ft increase with an increase in the dp and Va was given in Figure 6. K4 and K5 samples have high values of the Cf at the dp of 2.0 mm while T1, T2, and T3 samples have low values of the Cf at the dp of 1.2 mm. Processability of the Cf values of K4 and K5 samples the dp of 2.0 mm is more forced than that of the other samples. K4 and K5 samples have high values of the Cf at a Va of 3.000 mm/min while T1, T2, and T3 samples have low values of the Cf at a Va of 2.000 mm/min. Processability of the Cf of K4 and K5 samples at a Va of 3.000 mm/min is more forced than that of the other samples.\n\n
In processability tests, the Sc and Se measurements were conducted using two-factor analysis of variance (ANOVA) (Sc and Se for 12 natural rocks × 3 dp × 3 Va) randomized experimental design with 100 replications (n = 100). A total of 30,600 data were obtained on the rocks. In terms of the Sc and Se, among the dp and Va there was a statistically significant difference (P < 0.001) (Table 9).\n
|Sc and Se dependent variable\n||dp (mm)\n||Mean difference (I-J)\n||Std. Error\n||Sig.\n||95% confidence interval\n|
|\n||Mean (I)\n||Mean (J)\n||Lower bound\n||Upper bound\n|
In processability tests for natural rocks, the mean Sc and Se values at the dp of 1.2 mm are lower than those at the dp of 1.6 and 2.0 mm was given in Figure 7. Sc and Se values at the Va of 2000 mm/min are higher than those at the Va of 2500 and 3000 mm/min. Sc and Se values at the Va of 3000 mm/min are lower for T1, T2, and T3 samples while those at the Va of 2000 mm/min are higher for both K4 and K5 samples. The natural rocks should have the Va of 3000 mm/min according to the Sc and Se values.\n\n
Regression models were applied to examine the relationship between the Cf and Sc values for each of the natural rocks. The results of the simple linear regression analysis are given in Figure 8.\n\n
Figure 8 shows that there is a statistically significant relationship between Sc and Cf values. Correlation coefficient (R2) values obtained from the natural rocks in the Fc at depths of cut of 1.2, 1.6 and 2.0 mm are 0.895, 0.871 and 0.859, respectively. Correlation coefficient (R2) values obtained from the natural rocks in the Ft at depths of cut of 1.2, 1.6 and 2.0 mm are 0.890, 0.878 and 0.880, respectively. Correlation coefficient (R2) values obtained from the natural rocks in the Fc at the Va of 2000, 2500 and 3000 mm/min are 0.771, 0.780 and 0.780, respectively. Correlation coefficient (R2) values obtained from the natural rocks in the Ft at the Va of 2000, 2500 and 3000 mm/min are 0.745, 0.781 and 0.781, respectively.\n
The results of the correlation coefficient and regression model are given in Figure 9. Correlation coefficient (R2) obtained from the natural rocks is 0.784, indicating that there is a linear relationship between the Sc and Se.\n\n
The relation between the Fc, Ft, Sc and Se values, and the physico-mechanical properties of the natural stones were evaluated through regression analysis. The results of the regression analysis are given in Tables 10 and 11, respectively.\n
|Independents/Cf\n||Dependents/physico-mechanical properties\n||Custom equation\n||R2 Linear Model\n|
|Fc\n||D\n||y = 3.506 * x + 2625.962\n||0.931\n|
|P\n||y = −0.035 * x + 1.595\n||0.923\n|
|WA\n||y = −0.031 * x + 1.356\n||0.887\n|
|KH\n||y = 1.982 * x + 99.007\n||0.976\n|
|UCS\n||y = 1.842 * x + 53.365\n||0.981\n|
|FS\n||y = 0.244 * x + 5.129\n||0.889\n|
|IS\n||y = 0.547 * x + 14.612\n||0.968\n|
|AR\n||y = −0.245 * x + 25.189\n||0.932\n|
|Ft\n||D\n||y = 3.588* x + 2627.838\n||0.930\n|
|P\n||y = −0.035 * x + 1.575\n||0.919\n|
|WA\n||y = −0.031 * x + 1.338\n||0.883\n|
|KH\n||y = 2.030 * x + 100.026\n||0.978\n|
|UCS\n||y = 1.217 * x + 42.861\n||0.983\n|
|FS\n||y = 0.251 * x + 5.237\n||0.896\n|
|IS\n||y = 0.560 * x + 14.902\n||0.968\n|
|AR\n||y = −0.251 * x + 25.047\n||0.928\n|
|Independents/Sc and Se\n||Dependents/physico-mechanical properties\n||Custom equation\n||R2 linear model\n|
|Sc\n||D\n||y = 2.017* x + 2630.804\n||0.929\n|
|P\n||y = −0.020*x + 1.547\n||0.922\n|
|WA\n||y = −0.017 * x + 1.314\n||0.887\n|
|KH\n||y = 1.142 * x + 101.696\n||0.977\n|
|UCS\n||y = 0.684 * x + 43.858\n||0.983\n|
|FS\n||y = 0.140 * x + 5.456\n||0.892\n|
|IS\n||y = 0.315 * x + 15.357\n||0.968\n|
|AR\n||y = −0.141 * x + 24.845\n||0.929\n|
|Se\n||D\n||y = 115.7 * x + 2166.149\n||0.858\n|
|P\n||y = −1.032 * x + 5.610\n||0.686\n|
|WA\n||y = −0.883 * x + 4.766\n||0.616\n|
|KH\n||y = 63.347 * x + −151.219\n||0.844\n|
|UCS\n||y = 37.511 * x + −105.578\n||0.829\n|
|FS\n||y = 8.647 * x + −29.663\n||0.944\n|
|IS\n||y = 17.500 * x + −54.520\n||0.837\n|
|AR\n||y = −7.476 * x + 54.445\n||0.732\n|
Correlation coefficient (R2) values of the natural rock samples, a linear relationship between the Cf values and the physicomechanical characteristics is observed. As a result of the analysis, the following correlation coefficient (R2) values have been obtained: R2 coefficient range from 0.887 to 0.981 in the Fc and from 0.883 to 0.983 in the Ft. All values confirm the linear relationship among physicomechanical properties in natural rocks with the Cf. Accordingly, as porosity, water absorption and abrasion strength decrease in the natural rocks, Cf values increases. Moreover, as knoop hardness, uniaxial compressive strength, flexural strength and impact strength increase, the Cf values also increase.\n
Correlation coefficient (R2) values of the natural rock samples, a linear relationship between the Sc and Se values and the physicomechanical characteristics is observed. As a result of the analysis, the following correlation coefficient (R2) values have been obtained: R2 coefficient range from 0.887 to 0.977 in Sc and from 0.616 to 0.858 in the Se. All values confirm the linear relationship among physicomechanical characteristics in natural rocks with the Sc and Se. Accordingly, as porosity, water absorption and abrasion strength decrease in the natural rocks, Sc and Se value increases. Moreover, as Knoop hardness, uniaxial compressive strength, flexural strength and impact strength increase, the Sc and Se values also increases.\n
Proper selection and performance estimation of mill cutting tools are important factors in improving the efficiency of processability and decrease costs in natural rocks. Performance cutting parameters and 3D design of mill cutting tools are cutting tool diameter, dp, Va, Fc, and Ft, Sc and Se. A contribution was made to the literature by proposing new correlation coefficients (R2) for natural rocks.\n
The rocks in this study were determined according to by taking into account the Cf, Sc and Se. value in accordance with the statistical analyses. Cf, Sc and Se values vary depending on the dp and Va used in natural rocks. Results of the experimental study are summarized below:
Fc and Ft values are high at the dp of 2.0 mm and Va of 3.000 mm/min.
Sc and Se, values are high at the dp of 1.2 mm and Va of 2.000 mm/min.
Due to the increased friction force due to the increase in the amount of natural rock chips to be cut by the cutter edge at the dp of 2.0 mm, the processability is most difficult.
The cutting parameters with the highest specific energy volume are considered to be the toughest moments of the CNC machine.
The values of Sc and Se are reduced and the efficiency increases with an increase in the dp which results from the increase in the cutting edge of the chip volume in natural rocks. Sc and Se are significantly increased at the dp of 1.2 mm.
There is a significant relationship between Cf, Sc and Se depending on the dp and Va, the correlation coefficient (R2) values of which are 0.859 to 0.895, and 0.745 to 0.781 respectively.
A significant relationship between the Sc and Se was identified as R2 (0.784).
There is a significant relationship between the Cf and physicomechanical properties. R2 ranges from 0.887 to 0.981 in the Fc and from 0.883 to 0.983 in the Ft.
There is a significant relationship between the Sc, Se, and physicomechanical properties. R2 ranges from 0.887 to 0.983 in the Sc and from 0.616 to 0.944 in the Se.
This study was supported (Project number: 13.GÜZSAN.01 and TR33/12/SKMDP/0104). We would like to thank them for their (Afyon Kocatepe University and Zafer Development Agency) support and contributions.\n
Crush injuries of the hand pose a challenge to even the most accomplished of hand surgeons, whether it is a minor fingertip injury sustained by getting squashed in a closing door or a high pressure compression injury involving the palm or wrist.
A crush injury is defined as compression of the extremities causing muscular and neurological disturbance  and in the upper limb is sustained when the fingers, hand or wrist are caught between two surfaces (sharp, blunt, smooth or irregular) forcibly producing damage to the skin and its enclosed contents of soft tissues and bone. The degree of damage is proportional to the amount of force applied per square inch and the duration the compression is in place. Thus a crushing element is present in almost all hand injuries be it distributed over a narrow segment as in a guillotine amputation of a finger or diffusely spread as in a roller injury.
Prolonged compression in heavy machinery in a more proximal part of the limb may induce additional systemic sequelae known as the crush syndrome. This was first described in the German language literature by Von Colmers, following the 1909 Messina earthquake and by Frankenthal during the 1916 World War I air raids as cited in Better . The English Language literature, however, was only enlightened by Bywaters and Beall after the 1940 London ‘Blitzkrieg’ of World War II, where they outlined the pathogenesis of crush syndrome and its potential systemic effects of myoglobinuria leading to acute renal failure causing the patient’s demise hours or even days later . He described alkalinisation of urine as a method to prevent the acute renal failure and subsequent deterioration, which has stood the test of time. Michaelson defined continuous prolonged pressure on the limbs of at least 4 hours duration prior to extrication as causing crush syndrome . Fortunately, crush injuries to the hand distal to the wrist have less systemic manifestations primarily due to a smaller muscle bulk. They are however otherwise no less dramatic and have evolved over the years associated with technological developments in human endeavours (Table 1).
|Time and causative factor||Authors||Year|
|Machines on the farm|
|Corn picker injury||Robinson and Hardin||1955|
|Campbell DC et al.||1979|
|Gorsche and Wood||1988|
|Grain auger injury||Grogono||1973|
|Beatty et al.||1982|
|Woodwork related mishaps|
|Chain saw injuries||Haynes et al.||1980|
|Wood splitter injuries||Jaxheimer et al.||1981|
|Wool carder||Smith and Asturias||1968|
|Wringer injury||MacCollum et al.||1952|
|Meat mincers||Al-Arabi and Sabet||1984|
|Sugarcane juice extracting machine||Rajput and Daver||1999|
|Dough sheeter||Carriquiry and Arganaraz||2005|
|Noodle-making machine||Ju et al.||2015|
|Rotary lawn mowers and snowblowers||Barry and Linton||1977|
|Roll over injury||Harris and Wood||1978|
|Roll bar hand||Charters and Davis||1978|
|Overturning motor vehicle||Mehrotra and Crabb||1979|
|Roping injury||Kirwan and Scott||1988|
|Pay phone receiver cord||Lesavoy||1984|
|Soccer||Curtin and Kay||1976|
|Karate||Nieman and Swann||1977|
This period brought about some of the most devastating effects from the corn picker injury as first described by Robinson in 1955 and later by Campbell in 1979 and then Gorsche in 1988 [5, 6, 7], and later by the equally if not more devastating Grain Auger injury which cut swathes at multiple levels [8, 9]. In the mid 1960s to early 1970s when the oil embargo of the Arab states diverted energy sources away from fuel to firewood, a higher incidence of injuries with wood working tools was reported by Heycock in 1966 , the modern (and fatalistic) version of which is the chainsaw or circular saw injury (Figure 1)  and the motorised wood splitter injury . The advent of industrialisation into the agricultural sector saw farm machinery and farm-related injuries coming into the scene in the 1980s and 1990s being a challenge due to the high contamination [13, 14].
The advent of the industrial age saw its own share of mutilation with workers spinning wool on an electrical wool carder  sustaining a unique injury thereof with the fingers undergoing a crush and the spikes inflicting a horrific-looking but benign injury (Figure 2).
Children were the victims in 80% of “The Wringer Injury” as cited by MacCollum was first described in 1938 . It wreaked havoc for 45 years till production was stopped in 1983 via legislation . In the late 1960s and early 1970s, there was a flood of children getting their hands caught in escalators and meat mincers each presenting with their unique brand of mechanism and challenge [19, 20]. The former primarily caused a deep avulsion or a degloving (Figure 3), while the latter had two levels of injury: a multilevel cutting injury first like a miniature auger (Figure 4) and a mincing mechanism sustained later.
Peculiar but not exclusive to South and South East Asia is the sugarcane juice extraction machine which was described in 1999  and has also evolved from manual to electric. This produced devastating injuries similar to the dough sheeter injury  with components of grinding, compression and avulsion, making it difficult to salvage digits . In our experience, most end up with a metacarpal hand for the machine is very unforgiving and the infection due to bacterial contamination challenging to eradicate, requiring meticulous, repeated débridements in the primary setting (Figure 5). Another unique Asian injury is the noodle machine, which causes a degloving injury (Figure 6), of which in the English literature only one article mentions it in passing . A more widespread but less reported one is the coconut grinding machine which causes a similar injury to the grain auger (and meat mincer) but of a smaller scale (Figure 7).
In the vehicle category is the powered industrial vehicle (PIV) and although the literature describes how 70% of PIV injuries are attributable to forklifts , there are no specific articles on hand injuries caused by forklifts . This is we feel a special entity which needs to be dealt with because it causes extensive damage to the skeleton as well as the soft tissues and needs rigid and rapid fixation best achieved with a simple form of mini external fixator (Figure 8). Spring and winter brought their own brand of injuries in rotary lawn mowers and snow blowers , while the motor vehicle left its own special mark, described as the roll over injury or roll bar hand in 1978 by Harris and Charters, respectively [29, 30] and subsequently by Mehrotra and Crabb as hand injuries sustained in the overturning motor vehicle . Typically, the victim would have the hand outside the window during the accident or it is grazed along the gravel – what we call the “brake pad injury” (Figure 9).
In this era, electrical equipment and wiring had peculiar stringing injuries as described by Morgan in 1984  and as roping by Kirwan and Scott in 1988 . Pay phone receiver cords  and power drill cords also cause similar injuries where the cord wraps around the hand or forearm like a vise cutting off blood supply and causing ischaemia to the limb (Figure 10).
A number of different types of hand injuries have been described while playing soccer but these are mostly fractures or associated ligamentous injuries with less of a crushing element to the tissues . Karate is a sport, which may cause a crush injury to the hand or forearm since the hand is used as a weapon to demolish bricks and other hardware .
Thus we can see the spectrum of change in the pattern of crushing injuries to the hand but though the cause may be different, the mechanism and resultant effects still pose a challenge to the modern-day hand surgeon.
The pathomechanics of a crush injury will vary according to the manner in which the injury was sustained. The damage done is related to the force of the injury (both in magnitude and direction), the velocity of the impact and the surface area of the crushing. The damage sustained is also dependant on the site of injury, the surrounding skin and its contents.
Therefore, the zone of injury sustained is a function of the applied force, the velocity and the width of the offending object. These three main factors will determine the outcome and extent of the injury. The duration of compression as well as compounding factors such as friction, heat, cold, chemicals and contamination add further damage to the injured area.
The force may be a low-energy mechanism with resultant closed injury and fewer stigmata of damage. Typically, this may be due to a door or a drawer closing on the fingertip producing a subungual haematoma, a nailbed injury, a mallet deformity or a tuft fracture of the distal phalanx (Figure 11). The milder ones may not even present at the casualty department but may be seen later in the clinic. A more severe form seen especially in children called a Seymour Fracture occurs where the nail plate is avulsed proximally with an associated nailbed injury and a distal phalanx (P3) fracture (Salter Harris I) through the epiphysis (Figure 12). The middle finger being the longest is most commonly involved. Soft tissue interposition and instability dictate operative repair and fixation otherwise complications may include infection, nail disturbances, growth arrest and deformity .
A high energy force with a high velocity of impact would cause serious damage not only at site of impact but can cause degloving of the proximal part as well, from the dynamic force of the hand pulling away. These injuries are sustained in a road traffic accident or high pressure punch presses such as printing presses (Figure 13).
The crushing mechanism may be uniplanar as in a heavy object falling from a height onto the hand or multiplanar with either an associated torsional or a tractional force. Grain augers exert a torsional force and are used for raising grain and they cause characteristic multiple swathes equidistant to the spiral turns of the auger blade drawing the limb in with each turn (Figure 14). A similar mechanism is used in the meat mincer and the coconut grating machine (Figures 4, 7). An example of a tractional force can be seen in Roller belt injuries (Figure 15) as well as those due to the sugarcane juice extracting machine where severe avulsion or degloving of tissues can occur due to the pulling action, along with devastating superinfection due to microbial (Pseudomonas Ae) contamination .
The width of the instrument of injury determines the depth and extent of bone and soft tissue damage.
Therefore, for the same force, the smaller the unit area, the higher the pressure concentrated over that minute area. Thus a sharp instrument with a lesser amount of force (sharp knife = amputation) might slice through tissue whereas a compression over a wider area (hammer = burst laceration) would cause more of a crushing injury.
The direction of the force is also important, whether it is along the tissue planes or perpendicular to it. Thus a vessel may be sliced in a transverse fashion – in case of a complete transection, it will go into spasm and contract, but a partial one may be held open and still bleed – or scathed along its length (Figure 16). The latter will usually present with hypovolaemic shock due to profuse uncontrollable bleeding. Pressure dressing should be applied and exploration performed in the operating room.
The dorsum of the hand has minimal soft tissue padding and is relatively vulnerable to bony injury. A metacarpal fracture commonly occurs with a direct blow on the dorsum of the hand. Bony injury often results from the high energy impact of blunt objects related to the factors of force, velocity and width of the striking objects and may present in a spectrum of varying depths of involvement and comminution (Figure 17), from periosteal stripping, to unicortical fracture, to transverse, oblique, spiral or comminuted fracture, to segmental fracture and segmental bone loss.
Soft tissues over the palmar aspect are fairly well protected by the thick and highly sensitive glabrous skin. Neurovascular bundle and flexor tendon injuries are seldom seen in closed injuries. In open fracture of the phalanges, associated neurovascular and flexor tendon injuries must be looked for. The flexor tendons are very resistant to injury and usually are the last to be severed (Figures 5 and 15B). In the mid-palmar space, which is a relatively confined region holding soft tissues contained by a thick fascia, a sudden compression with high pressure may lead to bursting injuries, resulting in rupture and extrusion of muscles (Figures 18, 19).
Thermal necrosis may be present due to friction, as in roller injuries or heat, chemical and electrical burns which cause either partial or full thickness skin loss or due to hot compression presses which result in full thickness loss even up to the deep muscle layer of the hand (Figure 20).
The roller injury is special in that it commonly results in distally based avulsion flaps and may be associated with friction burns . The size of the gap between the rollers as well as the padding is important to determine the amount and force of crushing. If there is an automatic stop mechanism, there is some tendency to minimise damage. An examiner should not be foxed by superficial friction burns. A degloving injury of skin and deep tissues may not be apparent especially in a closed injury or incomplete avulsion. The resultant shearing off of blood vessels in the subcutaneous plane may lead to secondary thrombosis of the blood vessels resulting in fat necrosis and delayed necrosis of overlying skin . A direct injury to the muscle or a compromised circulation of the forearm and hand may eventually lead to Volkmann’s ischaemic contracture, an early symptom of which is pain on extension of the digits (Figure 21). A narrow gap in the rollers would inevitably involve severe crushing of muscles, nerves and the skeletal framework. For the novice, a simple guide to the extent of crushing may be evaluated by the degree of bony comminution in the X-ray (Figure 22).
Compression of muscular segments of the limb is the basic mechanism underlying the pathogenesis of crush syndrome. The relative contribution of compression leading to ischaemia of the muscles and direct injury to the muscle leading to necrosis is difficult to separate. Mechanical compression alone with an adequate vascular supply (warm periphery with palpable pulses) has been shown to cause significant pathological changes in skeletal muscle by as early as 60 minutes as shown by Better and Stein and cited in Burzstein and Carlson . This compares unfavourably to a warm ischaemic time of 6 hours – without compression , leading Burzstein and Carlson to conclude that skeletal muscle is more sensitive to mechanical compression than ischaemia. This may be due to the fact that in compression intramuscular pressures may reach as high as 240 mmHg  which is thought to compromise the microvasculature of skeletal muscle. This may cause alteration in myocyte function in terms of calcium flux across mitochondrial and plasma membranes.
In ischaemic injury however, reperfusion results in further damage to skeletal muscle resulting in the coinage of the term “reperfusion injury”. The offending substances are O2-derived free radicals such as super oxide, H2O2 and hydroxyl ions, which cause parenchymal and microvascular endothelial damage especially with reperfusion. Compounds such as super oxide dismutase (SOD) and catalase which when administered, inhibit or neutralise these radicals, have been shown to limit the reperfusion injury in the affected tissue and its microvasculature [43, 44].
Krapohl et al.  showed that a crush injury to the arteries supplying the cremasteric muscle in rats resulted in a significant decrease in skeletal muscle perfusion even though the blood supply though the crushed vessel is maintained and that this may be due to thrombogenic results.
In another interesting animal study, thrombolysis followed thrombosis in rat arteries with induced crush injuries . However, if the crushed arteries were divided and sutured with microvascular anastomosis almost all thrombosed (90%) unless they were irrigated with topical heparin solution which reduced the thrombosis rate but did not promote thrombolysis.
Both these studies show that localised crush injuries to the arteries deserve to be treated with respect and that all such tissue should be excised prior to microvascular anastomoses. It is also important to appreciate that the severity of the crushing may result in amputation of the digits and hand (Figure 5). In segmental crushing, however, the distal amputated part, for example, of the hand may be relatively uninjured (Figure 23).
A thorough understanding of the underlying mechanisms of injury will enable the primary surgeon to pay due diligence where required in detailed planning of the step by step management constantly deliberating carefully between damaged tissues to discard while treating with respect the tissues to be salvaged.
Roohi S.A. would like to thank Prof. Dr. Lim Beng Hai for his guidance as well as the use of some of his work in the Figures as acknowledged.
The authors declare no conflict of interest and have not received any remuneration or benefit from any entity for the writing or publication of this article.
|ADM||abductor digiti minimi|
|DIPJ||distal interphalangeal joint|
|FDP||flexor digitorum profundus|
|FDS||flexor digitorum superficialis|
|MVA||motor vehicle accident|
|P||phalanx 1: proximal, 2: middle, 3: distal|
|PIPJ||proximal interphalangeal joint|
|ROM||range of motion|
|RTA||road traffic accident|